Pinpoint Test AJ: P04B5, P04BA

WARNING: This page is about a different car, the 2021 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.

Normal Operation and Fault Conditions

The PCM monitors the fuel filler door ajar switch and sets a DTC if it detects a failure of the fuel filler door ajar input based on conditions after a refueling event.

If the fuel filler door is not fully closed after a refueling event, or the fuel filler door is open from erroneously pressing the fuel door release button, a message displays during the third drive cycle to indicate the fuel filler door is not closed and a DTC sets.

DTC Fault Trigger Conditions

DTC	Description	Fault Trigger Condition
PCM P04B5:00	Fuel Fill Door Stuck Open: No Sub Type Information	Sets when the PCM detects the fuel filler door is open, the vehicle has been running for at least 5 minutes and the vehicle speed is greater than 11 km/h (7 mph) (for example, the fuel filler door was not closed after a refueling event).
PCM P04BA:00	Fuel Fill Door Position Sensor/Switch Circuit High: No Sub Type Information	Sets when the PCM detects the fuel filler door did not open when the PCM activated the fuel filler door release relay. An open circuit to the fuel filler door ajar switch can cause this DTC to set.

Possible Sources

Wiring, terminals or connectors
Fuel filler door ajar switch (part of the fuel filler door housing)
PCM

NOTE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

AJ1 CHECK FOR MECHANICAL DAMAGE
- Ignition OFF.
- Inspect fuel filler door for damage near the ajar switch.
Is any damage present?

Yes REPAIR or INSTALL a new fuel filler door housing as necessary.

No GO to AJ2

AJ2 CHECK THE PCM (POWERTRAIN CONTROL MODULE) THE CUSTOMER IS REQUESTING OR HAS RECENTLY REQUESTED TO OPEN OR UNLOCK THE FUEL FILL DOOR (FUELDR_REQ) PID (PARAMETER IDENTIFICATION)
- Ignition ON.
- Access the PCM and monitor the FUELDR_REQ (none) PID
- Monitor the PCM FUELDR_REQ PID while pressing and releasing the fuel filler door release button.
Does the PID momentarily indicate Yes?

Yes GO to AJ3

No GO to Pinpoint Test AH

AJ3 CHECK THE FUEL FILLER DOOR RELEASE USING THE PCM (POWERTRAIN CONTROL MODULE) FUEL FILL DOOR UNLOCK CONTROL OUTPUT IS COMMANDED TO ENABLE STATE (FUELDR_UNLOCK) PID (PARAMETER IDENTIFICATION)
- Verify the fuel filler door is fully closed.
- Access the PCM and control the FUELDR_UNLOCK (none) PID
- Command the PCM FUELDR_UNLOCK PID On.
Does the fuel filler door latch release?

Yes GO to AJ4

No GO to Pinpoint Test AH

AJ4 CHECK THE PCM (POWERTRAIN CONTROL MODULE) THE FUEL FILL DOOR POSITION SENSOR/SWITCH CIRCUIT INPUT (FUELDR_POS_SW) PID (PARAMETER IDENTIFICATION)
- Close the fuel filler door.
- Access the PCM and monitor the FUELDR_POS_SW (none) PID
- Monitor the PCM FUELDR_POS_SW PID.
- Access the PCM and control the FUELDR_UNLOCK (none) PID
- Command the PCM FUELDR_UNLOCK PIDOn.
- Verify the fuel filler door latch released.
Does the PID indicate Closed with the fuel filler door closed and Open after the fuel filler door latch is released?

Yes The system is operating correctly. REFER to Normal Operation and Fault Conditions at the beginning of this Pinpoint Test.

No GO to AJ5

AJ5 CHECK THE FUEL FILLER DOOR AJAR CIRCUITS FOR A SHORT TO VOLTAGE

NOTE: The fuel filler door electrical connectors can be accessed through an opening in the left side sheet metal inside luggage compartment area.

Ignition OFF.

Disconnect Fuel Filler Door Release Solenoid C4089.

Disconnect PCM C175B.

Ignition ON.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C4089-2	Courtesy of FORD MOTOR COMPANY	Ground
C4089-3	Courtesy of FORD MOTOR COMPANY	Ground

Is any voltage present?

Yes	REPAIR the circuit in question.

GO to AJ6

AJ6 CHECK THE FUEL FILLER DOOR AJAR CIRCUITS FOR A SHORT TO GROUND

Ignition OFF.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C4089-2	Courtesy of FORD MOTOR COMPANY	Ground
C4089-3	Courtesy of FORD MOTOR COMPANY	Ground

Are the resistances greater than 10, 000 ohms?

Yes

GO to AJ7

No	REPAIR the circuit in question.

AJ7 CHECK THE FUEL FILLER DOOR AJAR CIRCUITS FOR AN OPEN

Measure:

Positive Lead	Measurement / Action	Negative Lead
C4089-2	Courtesy of FORD MOTOR COMPANY	C175B-7
C4089-3	Courtesy of FORD MOTOR COMPANY	C175B-80

Are the resistances less than 3 ohms?

Yes	INSTALL a new fuel filler door housing. CLEAR the Diagnostic Trouble Codes (DTCs) and repeat the self-test. If the concern is still present, GO to AJ8

No	REPAIR the circuit in question.

AJ8 CHECK FOR CORRECT PCM (POWERTRAIN CONTROL MODULE) OPERATION

Disconnect and inspect all the PCM connectors.

Repair:
- corrosion (install new connectors or terminals - clean module pins)
- damaged or bent pins - install new terminals pins
- pushed-out pins - install new pins as necessary

Reconnect the PCM connectors and make sure they seat and latch correctly.

Operate the system and determine if the concern is still present.

Is the concern still present?

Yes

CHECK OASIS for any applicable service articles: TSB, GSB, SSM, or FSA. If a service article exists for this concern, DISCONTINUE this test and FOLLOW the service article instructions. If no service articles address this concern, refer to PCM GUIDED ROUTINE TESTING
Internet Explorer version 11 or greater is required to perform this Pinpoint Test.

No	The system is operating correctly at this time. The concern may have been caused by module connections. ADDRESS the root cause of any connector or pin issues.